The present invention relates to a refrigeration system for cooling electrical components. More particularly, the invention relates to a multiple compressor refrigeration heat sink module that is suitable for use in standard electronic component environments.
Electronic components, such as microprocessors and other various integrated circuits, have advanced in at least two significant ways. First, feature sizes have moved into the sub-micron range thereby allowing larger numbers of transistors to be formed on a given surface area. This in turn has resulted in greater device and circuit density on the individual chips. Second, in part due to the first advance discussed above, microprocessors have increased dramatically in clock speed. At present microprocessor speeds of 2.5 Gigahertz are coming to market and the 3 and 4 Gigahertz range is rapidly being approached.
As a result of the advances in device density and microprocessor speed discussed above, heat dissipation, which has always been a problem in the past, is rapidly becoming the limiting factor in microprocessor performance. Consequently, heat dissipation and cooling is now the foremost concern and the major obstacle faced by system designers.
As noted, heat dissipation has long been recognized as a serious problem limiting the performance of electronic components and systems. In the past, the solutions to the heat dissipation problem have been mostly limited to air-based cooling systems, with only the most exotic military, scientific and custom electronic systems employing the bulky and costly prior art liquid-based cooling solutions.
In the prior art, air-based cooling systems, such as heat sinks, cooling fins, heat pipes and fans, have been the systems of choice for several reasons. First, the air-based cooling systems of the prior art were modular and self-contained and were therefore field replaceable with minimal effort using standard tools. Second, the prior art air-based cooling systems attached directly to the components that needed cooling and a discrete cooling unit could be provided for each heat source. In addition, air-based cooling systems were compact and simple in both operation and installation, with minimal parts to fail or break and minimal added system complexity. Therefore, prior art air-based cooling systems were very reliable. In addition, and probably most importantly, in the prior art, air-based cooling systems could reasonably meet the cooling needs of electronic devices and systems so there was little motivation to move to the more complex and problematic liquid-based systems. However, as noted above, due to the advances in microprocessor speeds and device density, air-based cooling systems will most likely not be a viable option for electronic device cooling for the next generation of microprocessors.
As noted above, another possible prior art cooling system that could potentially provide the level of cooling required by the next generation of microprocessors is liquid-based cooling systems. Prior art liquid-based cooling systems typically used a refrigerant, such as R134, that was circulated by a compressor. In prior art liquid-based cooling systems the compressor was typically a crankshaft reciprocating compressor or a rotary compressor similar to those used in home refrigerators.
As noted above, prior art liquid-based cooling systems have far more potential cooling capability than air-based systems. However, in the prior art liquid-based cooling systems, the crankshaft reciprocating or rotary compressors were typically, by electronics industry standards, very large, on the order of tens of inches in diameter, very heavy, on the order of pounds, and often required more power to operate than the entire electronic system they would be charged with cooling. In addition, the size and design of prior art liquid-based cooling systems often required that the major components of the prior art liquid-based cooling system be centrally located, typically remote from the electronic devices to be cooled, and that a complicated system of tubing or xe2x80x9cplumbingxe2x80x9d be used to bring the cooling liquid into thermal contact with the heat source, i.e., with the microprocessor, multi-chip module, or other integrated circuit. Consequently, unlike prior art air-based cooling systems, prior art liquid-based cooling systems were not modular, were not self-contained, and often required special expertise and tools for maintenance and operation. In addition, unlike the prior art air-based cooling systems discussed above, prior art liquid-based cooling systems did not attach directly to the components that needed cooling and a discrete cooling unit typically could not be provided for each heat source. Also, unlike the prior art air-based cooling systems discussed above, prior art liquid-based cooling systems were not compact and were not simple in either operation or installation. Indeed, prior art liquid-based cooling systems typically included numerous parts which could potentially fail or break. This added complexity, and threat of component failure, was particularly problematic with respect to the associated plumbing discussed above because a failure of any of the tubes could result in the introduction of liquid refrigerant into, or onto, the electronic devices and could cause catastrophic system failure.
In addition, prior art liquid-based cooling systems employed compressors that typically were highly orientation dependent, i.e., they could not operate at angles of more than 30 or 40 degrees. Consequently, prior art liquid based cooling systems were particularly ill suited for the electronics industry that stresses flexibility and often requires orientation independent operation.
In addition, prior art liquid-based cooling systems used large amounts of oil for compressor operation. This represented minimal problems in most refrigeration uses, however, in the electronics industry, the use of oil is problematic in terms of system operation, maintenance, potential leaks and weight.
Given that, as discussed above, air-based cooling systems have reached their operational limits when it comes to cooling electronic components, there is a growing realization that some other form of cooling system, such as liquid-based cooling systems will need to be adopted by the electronics industry. However, as discussed above, prior art liquid-based cooling systems are far from ideal and, thus far, the industry has not adopted liquid-based cooling in any meaningful way because the problems associated with prior art liquid-based cooling systems are still thought to outweigh the advantages these systems provide in terms of increased cooling capacity.
What is needed is a cooling system that has the cooling capacity of a liquid-based cooling system yet has the advantages of being modular, simple, and compact and highly reliable like air-based cooling systems.
The present invention is directed to a multiple compressor refrigeration heat sink module that is suitable for use in standard electronic component environments. According to the present invention, advances in compressor technology are incorporated in a multiple compressor refrigeration heat sink module to be used for cooling electronic components.
The multiple compressor refrigeration heat sink module of the invention is self-contained and is specifically designed to have physical dimensions similar to those of a standard air-based cooling system. As a result, the present invention can be utilized in existing electronic systems without the need for significant system housing modification or the xe2x80x9cplumbingxe2x80x9d associated with prior art liquid-based cooling systems. Indeed, unlike prior art liquid-based cooling systems, in one embodiment of the invention, the various parts of the multiple compressor refrigeration heat sink module of the invention, including the very minimal tubing, are self-contained in the multiple compressor refrigeration heat sink module and therefore a failure of any of the tubes would typically not result in the introduction of liquid into, or onto, the electronic devices and would not cause catastrophic system failure, as was the risk with prior art liquid-based cooling systems.
The multiple compressor refrigeration heat sink module of the present invention is a modified liquid-based cooling system and therefore provides the cooling capacity of a prior art liquid-based cooling systems. However, unlike prior art liquid-based cooling systems, in one embodiment of the invention, the multiple compressor refrigeration heat sink module of the invention is modular and self-contained and is therefore field and/or customer replaceable with minimal effort using standard tools. In addition, unlike prior art liquid-based cooling system, the multiple compressor refrigeration heat sink module of the invention is capable of being attached directly to the components that need cooling and, in one embodiment of the invention, a discrete multiple compressor refrigeration heat sink module of the invention can be provided for each heat source. In addition, unlike prior art liquid-based cooling systems, the multiple compressor refrigeration heat sink module of the invention is compact and simple in both operation and installation, with minimal parts to fail or break and minimal added complexity. Therefore, unlike prior art liquid-based cooling systems, the multiple compressor refrigeration heat sink module of the invention is sturdy and reliable.
In addition, the multiple compressor refrigeration heat sink module of the present invention is specifically designed to be operational in any orientation. Consequently, unlike prior art liquid-based cooling systems, the multiple compressor refrigeration heat sink module of the present invention can be mounted, and operated, at any angle. This makes the multiple compressor refrigeration heat sink module of the present invention particularly well suited for use with electronic systems.
In addition, since the multiple compressor refrigeration heat sink modules of the invention include multiple compressors, they are ideal for use in applications, such as multi-chip module and mainframe applications, where more cooling capacity is required and/or a higher degree of system reliability and efficiency is necessary.
In addition, by employing multiple compressors, the multiple compressor refrigeration heat sink module of the invention can provide more cooling capacity without resorting to a larger single compressor. Consequently, multiple compressor refrigeration heat sink modules of the invention are more flexible in terms of the resulting module dimensions. Therefore, the multiple compressor refrigeration heat sink modules of the invention have a flexible, and smaller, footprint that more easily fit into smaller spaces and existing system housings. Thus, using the multiple compressor refrigeration heat sink modules of the invention, there is no need to design a system with the compressor removed from the heat source. This avoids the space and plumbing complications associated with remotely located compressors.
In addition, multiple compressors provide the multiple compressor refrigeration heat sink modules of the invention with component redundancy and a safety backup mechanism. This is particularly advantageous in systems, such as mainframe computers, where components, such as multi-chip modules, cannot be xe2x80x9chot-swappedxe2x80x9d out and the entire system must be shut down in order to remove and/or replace the faulty module. By employing multiple compressors, the multiple compressor refrigeration heat sink modules of the invention provide a redundancy whereby if one compressor fails, the other compressor can be used to keep the xe2x80x9ccold-swapxe2x80x9d system safely up and running until a convenient time is found to shut down the entire xe2x80x9ccold-swapxe2x80x9d system to make repairs.
In one embodiment of the invention, one compressor is typically on and the other compressor is in standby. In this embodiment of the invention, a compressor control mechanism is typically a simple toggle switch that applies power to the operational xe2x80x9cstandbyxe2x80x9d compressor in the event of failure of the main compressor. In other embodiments of the invention, the multiple compressors time-share so that no one compressor is worn out faster than the other. In this embodiment of the invention, the compressor control mechanism is a simple toggle switch connected a timer circuit to apply power to the compressors on a time-sharing basis.
In addition, in one embodiment of the invention, multiple compressors provide the multiple compressor refrigeration heat sink modules of the invention with parallel operation capability. In this embodiment of the invention, the cooling load at any given time is shared between compressors. Load sharing is advantageous because it is typically easier on the compressors, since no single compressor is forced to carry the entire load.
In addition, parallel operation allows for variable cooling capability. In this embodiment of the invention, the compressor control mechanism works to increase the cooling capacity provided by compressors of the multiple compressor refrigeration heat sink modules of the invention in response to an increase in heat generated by the heat source. Consequently, the multiple compressor refrigeration heat sink modules of the invention have the capability to respond to an increase in microprocessor activity or ambient system temperature. This is a distinct improvement over single compressor systems that were designed to simply continuously run at a level that would provide cooling for a xe2x80x9cworst-casexe2x80x9d heat load, regardless of the actually heat load and the actual cooling required. Consequently, the multiple compressor refrigeration heat sink modules of the invention can provide adequate cooling, but avoid overcooling and the problems associated with overcooling such as condensation, excessive power use, and unnecessary component wear and tear.
In one embodiment of the invention, the variable cooling capability is accomplished by any one of several capacity control mechanisms well known in the art of standard refrigeration such as: a hot gas bypass mechanism; an evaporator driven pressure regulator mechanism; or a suction gas throttling mechanism. Hot gas bypass mechanisms, evaporator driven pressure regulator mechanisms, suction gas throttling mechanisms, and most other mechanical cooling capacity control schemes or mechanisms, have the advantage of increased reliability since these systems typically do not require electronics and have minimal, or no, moving parts to wear out or otherwise fail. Consequently, embodiments of the multiple compressor refrigeration heat sink modules of the invention using these mechanical cooling control schemes are particularly robust and low maintenance.
As a result of the features of the multiple compressor refrigeration heat sink modules of the present invention, discussed in more detail below, the multiple compressor refrigeration heat sink modules of the present invention can meet the cooling needs of multi-chip module and main frame systems, as well as other high heat producing systems, and can make further speed and device density improvements in microprocessor design a workable possibility.